hig.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Cabral, Diogo
Publications (7 of 7) Show all publications
Panchal, R., Gomes, J., Cabral, D., Eleyele, A. & Lança, M. (2019). Evaluation of Symmetric C-PVT Solar Collector Designs with Vertical Bifacial Receivers. In: : . Paper presented at SWC/SHC 2019. Solar World Congress 2019, 4-7 November, Santiago, Chile.
Open this publication in new window or tab >>Evaluation of Symmetric C-PVT Solar Collector Designs with Vertical Bifacial Receivers
Show others...
2019 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Photovoltaic thermal (PVT) solar collectors can be an effective solution for system output improvement. Photovoltaic thermal collectors naturally have a more expensive receiver than simpler photovoltaic or thermal only collectors, therefore making concentration a more appealing solution to achieve cost reduction. However, concentrating systems need careful analysis on the design phase in order to optimize the annual output. In addition, for stationary (non-tracking) collectors, it is critical to determine the incidence angle modifier (IAM).For this reason, a reflector study was carried out to determine suitable reflector designs for a stationary concentrating PVT collector. The reflectors were simulated using a Monte Carlo raytracing software called Tonatiuh. The two selected reflectors designs were named “pure parabola” (PP) and “compound parabolic concentrator” (CPC). The concentration ratio of 1.2 and 1.6 were selected for each reflector designs, which means a total of 4 collector troughs. The next step involved the construction of the two selected C-PVT collector designs, which were built and subsequently tested by the authors. The IAM was assessed and discussed by simulation and outdoor testing in detail.The IAM results show similar decreases in longitudinal IAM for both the PP and the CPC CPVT collector for the 1.2 concentration factor. For the transversal IAM with 1.2 of concentration factor, the CPC over performs. For the 1.6 concentration prototype collectors, the results are fairly similar. Lastly, the annual output was also simulated and presented.

Keywords
CPVT, CPC, PP, Bifacial Receiver, IAM, Collector Testing, Ray Tracing, PV
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-30975 (URN)
Conference
SWC/SHC 2019. Solar World Congress 2019, 4-7 November, Santiago, Chile
Available from: 2019-11-15 Created: 2019-11-15 Last updated: 2019-11-29Bibliographically approved
Chacin, L., Rangel, S., Cabral, D. & Gomes, J. (2019). Impact study of operating temperatures and cell layout under different concentration factors in a CPC-PV solar collector in combination with a vertical glass receiver composed by bifacial cells. In: SWC-SHC (Ed.), Impact study of operating temperatures and cell layout under different concentration factors in a CPC-PV solar collector in combination with a vertical glass receiver composed by bifacial cells: . Paper presented at SWC/SHC 2019. Solar World Congree 2019, 4-7 November, Santiago, Chile.
Open this publication in new window or tab >>Impact study of operating temperatures and cell layout under different concentration factors in a CPC-PV solar collector in combination with a vertical glass receiver composed by bifacial cells
2019 (English)In: Impact study of operating temperatures and cell layout under different concentration factors in a CPC-PV solar collector in combination with a vertical glass receiver composed by bifacial cells / [ed] SWC-SHC, 2019Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Solar Collectors with Compound Parabolic Concentrator (CPC) reflectors redirect solar irradiance into the receiver (placed in optimal position). The concept of such devices is to reduce the installation area and energy costs [1]. This research focuses on the behaviour and efficiency of a stationary CPC-PV solar collector. Each trough of this collector has different concentration factors (1.25 and 1.66) with vertically placed bi-facial cell receivers. An analysis of the electrical efficiency is performed in order to evaluate the viability of a CPC geometry with a vertical bifacial PV receiver. Furthermore, an investigation on bifacial cells performance due to concentration (and consequently increased cell temperature) is carried out. A numerical simulation of the yearly available radiation and the Incident Angle Modifiers (IAM) for each geometry is also conducted. Finally, a comparison between the simulations and the outdoor testing on the prototype collector is detailed. The tests took place in Gävle, Sweden (61º Latitude). The results showed that higher concentration factors led to larger operating temperatures (114ºC for a concentration factor of 1.66 and 96ºC for a concentration factor of 1.25). Although this may compromise the cell performance and shorten the device’s life cycle, it is shown that appropriate ventilation will allow manageable operating temperatures.

Keywords
CPV, Photovoltaic, CPC, Bifacial Receiver, Monocrystalline Cells, Operating Temperatures, IAM, Cell Layout.
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-30976 (URN)
Conference
SWC/SHC 2019. Solar World Congree 2019, 4-7 November, Santiago, Chile
Available from: 2019-11-15 Created: 2019-11-15 Last updated: 2019-11-29Bibliographically approved
Cabral, D., Gomes, J. & Karlsson, B. O. (2019). Performance Evaluation of Non-Uniform Illumination on a Transverse Bifacial PVT Receiver in Combination with a CPC Geometry. Solar Energy, 194, 696-708
Open this publication in new window or tab >>Performance Evaluation of Non-Uniform Illumination on a Transverse Bifacial PVT Receiver in Combination with a CPC Geometry
2019 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 194, p. 696-708Article in journal (Refereed) Published
Abstract [en]

PVT collectors co-generate electricity and heat from the same gross area, thus achieving higher combined heat and electric yields. A comprehensive evaluation has been carried out on non-uniform solar irradiation profile distributions on four symmetric low concentration CPC PVT (LCPVT) solar collector design concepts. Additionally, an electrical and thermal performance evaluation of symmetric truncated LCPVT solar collectors based on a CPC reflector geometry with a central transverse bifacial PVT receiver has been carried out, through a numerical ray-tracing model software and a multi-paradigm numerical computing environment software. A simplified thermal (quasi-dynamic testing method for liquid heating collectors described in the international standard for solar thermal collectors ISO 9806:2017) and electrical performance models were employed to evaluate the LCPVT design concepts. The evaluation was carried out for heating Domestic Hot Water (DHW) for a Single Family House (SFH) in Fayoum (Egypt), where energy yields between 351 and 391 kWh/m2/year have been achieved. The non-uniform solar irradiation assessment showed that the PV cells are exposed to high levels of radiation due to the specific reflector geometry. Furthermore, the study showed that the CPC geometries are very sensitive to the shading effect, as partial shadowing is substantial for high incidence angles.

Keywords
CPC PVT collectorLCPVTTransverse bifacial PVT receiverIrradiation flux distributionPerformance evaluationRay-tracing
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-30967 (URN)10.1016/j.solener.2019.10.069 (DOI)2-s2.0-85074877472 (Scopus ID)
Available from: 2019-11-14 Created: 2019-11-14 Last updated: 2019-11-25Bibliographically approved
Costeira, J., Vieira, M., Hayati, A., Gomes, J. & Cabral, D. (2018). Development of a compact and didactic solar energy kit using Arduino. In: Haberle, A. (Ed.), PROCEEDINGS OF THE ISES EUROSUN 2018 CONFERENCE - 12TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY: . Paper presented at 12th International Conference on Solar Energy for Buildings and Industry (ISES EuroSun), 2018, Rapperswil, SWITZERLAND (pp. 1663-1667). INTL SOLAR ENERGY SOC
Open this publication in new window or tab >>Development of a compact and didactic solar energy kit using Arduino
Show others...
2018 (English)In: PROCEEDINGS OF THE ISES EUROSUN 2018 CONFERENCE - 12TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY / [ed] Haberle, A., INTL SOLAR ENERGY SOC , 2018, p. 1663-1667Conference paper, Published paper (Refereed)
Abstract [en]

When the sun rises, so does the key element that will shape the future of the world energy landscape. It is not an understatement to say that the solar energy industry is beginning to lead the path towards a sustainable future for all of us. However, the awareness of the potential of this amazing source of energy must begin from the most basic levels of education all the way to university. The scope of this paper is to display a new compact and didactic solar energy kit with the potential to replace current high cost and complex solar energy kits. These solutions are often too expensive and therefore unavailable for most of Europe’s public schools. As such, an equipment was developed using an open-source platform called Arduino that will enable students to conduct practical experiments in a fast, effective and simple manner and thus allow students to acquire the proper expertise in areas like energy, electronics, and programming.

Place, publisher, year, edition, pages
INTL SOLAR ENERGY SOC, 2018
Keywords
Photovoltaic (PV) cells; Solar energy; Teaching kit; Active learning; Arduino
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:hig:diva-30564 (URN)10.18086/eurosun2018.07.04 (DOI)000475550900174 ()
Conference
12th International Conference on Solar Energy for Buildings and Industry (ISES EuroSun), 2018, Rapperswil, SWITZERLAND
Available from: 2019-08-23 Created: 2019-08-23 Last updated: 2019-11-22Bibliographically approved
Cabral, D., Costeira, J. & Gomes, J. (2018). Electrical and Thermal Performance Evaluation of a District Heating System Composed of Asymmetric low concentration PVT Solar Collector Prototypes. In: Haberle, A. (Ed.), PROCEEDINGS OF THE ISES EUROSUN 2018 CONFERENCE - 12TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY: . Paper presented at 12th International Conference on Solar Energy for Buildings and Industry (ISES EuroSun), 2018, Rapperswil, SWITZERLAND (pp. 755-763). INTL SOLAR ENERGY SOC
Open this publication in new window or tab >>Electrical and Thermal Performance Evaluation of a District Heating System Composed of Asymmetric low concentration PVT Solar Collector Prototypes
2018 (English)In: PROCEEDINGS OF THE ISES EUROSUN 2018 CONFERENCE - 12TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY / [ed] Haberle, A., INTL SOLAR ENERGY SOC , 2018, p. 755-763Conference paper, Published paper (Refereed)
Abstract [en]

Photovoltaic-Thermal (PVT) solar collectors generate electricity and heat from the same gross area. The annual electrical and thermal yields of these systems are dependent on the PVT collector technology, as well as the climate and the type of solar thermal system implemented. This review presents an evaluation of a district heating system composed of 20 asymmetric hybrid low concentrator PVT (C-PVT) solar collector prototypes. The system is installed in a South wall facade in order to maximise the available space (with a tilt of 20 degrees and an orientation of 5 degrees W). The thermal system is connected to the district heating network, thus heating the University buildings. On the other hand, the electrical system is grid-connected, where it feeds the grid directly. Real measurement data has been collected and compared with a thermal (through ScenoCalc tool) and electrical performance models. The annual thermal and electrical yield achieved 86% and 89% of the simulated thermal and electrical yield, respectively.

Place, publisher, year, edition, pages
INTL SOLAR ENERGY SOC, 2018
Keywords
C-PVT; System analysis; Electrical and Thermal evaluation
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:hig:diva-30563 (URN)10.18086/eurosun2018.02.15 (DOI)000475550900080 ()
Conference
12th International Conference on Solar Energy for Buildings and Industry (ISES EuroSun), 2018, Rapperswil, SWITZERLAND
Available from: 2019-08-23 Created: 2019-08-23 Last updated: 2019-11-22Bibliographically approved
Cabral, D. & Karlsson, B. O. (2018). Electrical and thermal performance evaluation of symmetric truncated C-PVT trough solar collectors with vertical bifacial receivers. Solar Energy, 174, 683-690
Open this publication in new window or tab >>Electrical and thermal performance evaluation of symmetric truncated C-PVT trough solar collectors with vertical bifacial receivers
2018 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 174, p. 683-690Article in journal (Refereed) Published
Abstract [en]

One way to reduce solar collectors’ production costs is to use concentrators that increase the output per photovoltaic cell. Concentrating collectors re-direct solar radiation that passes through an aperture into an absorber/receiver. Symmetrical truncated non-tracking C-PVT trough collectors based on a parabola and compound parabolic concentrator (CPC) geometries have been developed. The collector type has a central vertical bifacial (fin) receiver and it was optimized for lower latitudes. In this paper, the electrical and thermal performance of symmetric truncated non-tracking low concentrator PVT solar collectors with vertical bifacial receivers is analysed, through a numerical ray-tracing model software and a multi-paradigm numerical computing environment. A thermal (quasi-dynamic testing method for liquid heating collectors described in the international standard for solar thermal collectors ISO 9806:2013) and electrical performance models were implemented to evaluate the design concepts. The evaluation was made for heating Domestic Hot Water for a Single Family House in Fayoum (Egypt), where CPC geometries with a concentration factor of 1.6 achieved 8 to 13%rel higher energy yields (in kWh/m2/year) than the Pure Parabola geometries.

Place, publisher, year, edition, pages
Elsevier Ltd, 2018
Keywords
Bifacial receiver, Electrical and thermal yield evaluation, Ray-tracing, Symmetric C-PVT collector
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-28322 (URN)10.1016/j.solener.2018.09.045 (DOI)000451499500065 ()2-s2.0-85053808056 (Scopus ID)
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2019-11-22Bibliographically approved
Cabral, D., Gomes, J., Dostie-Guindon, P.-A. & Karlsson, B. O. (2017). Ray tracing simulations of a novel low concentrator PVT solar collector for low latitudes. In: ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings: . Paper presented at SWC 2017: ISES Solar World Congress, SHC 2017: IEA SHC Solar Heating and Cooling Conference 2017; 29 October - 2 November 2017, Abu Dhabi, UAE (pp. 1068-1079). International Solar Energy Society
Open this publication in new window or tab >>Ray tracing simulations of a novel low concentrator PVT solar collector for low latitudes
2017 (English)In: ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings, International Solar Energy Society , 2017, p. 1068-1079Conference paper, Published paper (Refereed)
Abstract [en]

One way to reduce solar collector's production costs is to use concentrators that increase the output per photovoltaic cell. Concentrating collectors re-direct solar radiation that passes through an aperture into an absorber. The current study evaluates electrical performance of symmetric C-PVT solar collectors with a vertical bifacial receiver, through a numerical ray tracing model software, Tonatiuh. Several designs have been analysed, such as the Pure Parabola (PP) and MaReCo CPC geometries, both symmetric. Parameters such as concentration factor, electrical performance, transversal and longitudinal IAM (Incidence Angle Modifier), the influence of optical elements and influence of the length of the reflector in the shadow effect have been studied for different geometries. The simulations were performed for Mogadishu, Somalia and showed good results for the Pure Parabola collector (PPc) annual received energy, 379 and 317 kWh/m2/year for a focal length of 15 e 30 mm, respectively. A symmetrical double MaReCo CPC collector has been simulated with the annual received energy of 315 kWh/m2/year. The addition of the optical elements will decrease the annual received energy of the PPc by around 11.5%, where the optical properties (7.1%) and glass (4.1%) have the biggest impact in the annual received energy. Overall, symmetric geometries proved to be the most suitable geometries for low latitudes applications, being the geometry f1 (focal length of 15 mm) the best one. 

Place, publisher, year, edition, pages
International Solar Energy Society, 2017
Keywords
MaReCo CPC geometry, Pure Parabola collector, Symmetric C-PVT, Tonatiuh, C (programming language), Geometry, Optical properties, Photoelectrochemical cells, Photovoltaic cells, Rhenium compounds, Solar collectors, Solar heating, Solar power generation, Solar radiation, Concentrating collector, Concentration factors, Direct solar radiation, Electrical performance, Ray tracing simulation, Ray tracing
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-27631 (URN)10.18086/swc.2017.18.05 (DOI)2-s2.0-85050544604 (Scopus ID)978-3-9814659-7-6 (ISBN)
Conference
SWC 2017: ISES Solar World Congress, SHC 2017: IEA SHC Solar Heating and Cooling Conference 2017; 29 October - 2 November 2017, Abu Dhabi, UAE
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2019-11-22Bibliographically approved
Organisations

Search in DiVA

Show all publications